Abstract
BACKGROUND: Plasma exchange (PE) removes high-molecular-weight substances and is sometimes used for antineutrophil cytoplasmic antibody-associated vasculitis (AAV) with alveolar hemorrhage. Hypotension during PE is rare, except in allergic cases. We report a case of shock likely caused by increased pulmonary vascular resistance (PVR) during PE. CASE PRESENTATION: A 66-year-old man with pulmonary hypertension (PH) and glomerulonephritis was admitted with dyspnea. He had discontinued sildenafil prior to admission. Alveolar hemorrhage associated with AAV was suspected, and PE was performed. Soon after, he developed circulatory failure and hyperlactatemia. Echocardiography revealed right ventricular dilation, suggesting increased PVR. Inhaled nitric oxide (iNO) was administered, rapidly improving hyperlactatemia and oxygenation. The shock observed during PE was attributed to multiple factors, including the potential removal of sildenafil, which may have led to an increase in PVR. CONCLUSIONS: The shock was attributable to acute right heart failure caused by an exacerbation of PH, possibly due to sildenafil removal via PE, although other contributing factors could not be excluded.